The prime minister immediately announced that she would welcome a vote of no confidence in her own government, and would make time for it on Wednesday.

The Labour leader, Jeremy Corbyn, quickly confirmed he had tabled the motion, with the support of the leaders of all other opposition parties.

Corbyn told MPs: “This is a catastrophic defeat. The house has delivered its verdict on her deal. Delay and denial has reached the end of the line.”

May said if she survived the vote – which appeared likely, after the Democratic Unionist party said it would back her – she would hold cross-party meetings with senior parliamentarians “to identify what would be required to secure the backing of the house”.

Brexit-supporting Conservatives joined with opposition parties and the DUP to trounce the government in the “meaningful vote”, which the prime minister delayed before Christmas in the vain hope of winning over waverers.

Quick guide

After May's Brexit defeat - what happens now?

What does this defeat mean for the government?

It means that Theresa May's Brexit deal has not passed - and its record scale puts severe pressure on the prime minister. Immediately after she lost by 230 votes, Jeremy Corbyn tabled a no-confidence motion.

What is the procedure for a no-confidence vote?

Under parliamentary convention, if the official opposition tables a motion saying "That this house has no confidence in Her Majesty’s government", the expectation is that ministers will allow time for it promptly.

When will the vote on the no-confidence motion be?

The leader of the Commons, Andrea Leadsom, has said that Wednesday's debate will run from the end of prime minister's questions at about 12.45pm until 7pm, when there will be a vote.

What happens if Labour wins?

There would not be an immediate election; instead, there would be a period of 14 calendar days in which the government can seek to regain the confidence of MPs, or else another government can be formed.

If this does not happen, then parliament will be dissolved, with the standard 25 working-day gap needed before the election is held.

Since the provision has not yet been used, it remains unclear how, if at all, this grace period could potentially be used to form a different government, for example a coalition or a minority Labour administration.

Will Labour win?

The signs point to no. However much many Conservative MPs dislike May’s Brexit plan they are not keen on an election. Just as crucially, May’s DUP coalition partners, who voted against the Brexit deal, immediately pledged they would back the PM.

What does May do if she holds on?

She begins to dance around some form of Plan B. May said she would immediately start talks with both Tories and people in other parties “in a constructive spirit” to seek a deal that could win the support of the Commons.

Whatever happens, she must present a “motion in neutral terms” presenting her proposed next steps to the Commons by Monday. This could be amended, meaning in theory backbenchers with their own ideas could try to seize control of the process.

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May began the eighth day of the Brexit debate by making a last-ditch plea to colleagues to support her, warning them not to break their promise to the British people to deliver Brexit.

“This is the most significant vote that any of us will ever be part of in our political careers. After all the debate, all the disagreement, all the division, the time has now come for all of us in this house to make a decision. A decision that will define our country for decades to come,” she said.

“Together we can show the people we serve that their voices have been heard, that their trust was not misplaced.

May herself embarked on a last-ditch charm offensive on Tuesday, holding meetings with MPs including the European Research Group’s Steve Baker, who said the pair had held a “constructive and substantial conversation about the future”.

'What are you playing at?' The Commons Brexit debate in quotes

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Speaking just before the vote, the Labour leader, Jeremy Corbyn, said “the prime minister has treated Brexit as a matter for the Conservative party, rather than the good of the whole country”.

He called the government’s efforts to steer Brexit through parliament “one of the most chaotic and extraordinary parliamentary processes” he had experienced in 35 years as an MP.

The attorney general, Geoffrey Cox, had earlier warned his colleagues that if they did not accept the deal, they risked condemning Britain to the chaos of a no-deal Brexit. “It would be the height of irresponsibility for any legislator to contemplate with equanimity such a situation,” he said.

He argued that members of the public affected by no deal would say to MPs: “What are you playing at? What are you doing? You are not children in the playground. You are legislators, and this is your job.”

Both Labour and the Scottish National party withdrew amendments to the government’s motion at the last minute, to allow MPs a clean vote on the deal.

Just one amendment, tabled by the Brexiter John Baron and proposing a unilateral exit mechanism for the Irish backstop, was voted on and soundly defeated, by 600 votes to 24.

Throughout the turbulent period since she became prime minister in the wake of the shock referendum result in 2016, May has battled to unite her party over Brexit. Despite that, she faced a string of resignations, including two Brexit secretaries – David Davis and Dominic Raab – over the details of the deal.

The publication on Monday of letters between May and the European commission president, Jean-Claude Juncker, about the Irish backstop failed to win over Tory MPs who feared the UK could be trapped in a quasi-permanent customs union.

Downing Street said May opened her weekly cabinet meeting on Tuesday by saying the government was the servant of the people, and pledging to deliver the referendum result. She will now come under intense pressure to cede control of the next steps in the Brexit process to parliament.

A spokesman for Donald Tusk, the president of the European council, said: “We regret the outcome of the vote, and urge the UK government to clarify its intentions with respect to its next steps as soon as possible.”

Government defeats by more than 100 votes are vanishingly rare; the only ones recorded in the past century occurred during the minority Labour government of 1924. Postwar, the only government defeats on a similar scale were by 89 in 1979, and 86 in 1978.